Btw, here are a few example variants of `L` sum :: Num a => L a a sum = L id (+) 0 prod :: Num a => L a a prod = L id (*) 1 list :: L a [

Btw, here are a few example variants of `L` sum :: Num a => L a a sum = L id (+) 0 prod :: Num a => L a a prod = L id (*) 1 list :: L a [a] list = id (\r a -> a : r) []